Semiconductors GaN, AlGaN -- Questions about abbreviations

Join the discussion
Ask a follow-up here, or get your own question answered by working scientists, mathematicians and engineers — people, not an autocomplete.
Real named experts · corrections over time · the nuance an AI answer skips
Sign up Log in
5 replies · 2K views
Deleted member 655103
Hi, I have some chemical abbreviation which I do not understand. Please can you tell me what those abbreviations mean?

1. u-GaN 800nm (C:2E16 at/cm3) (I do not understand what "u" stands for; GaN is Gallium Nitride, 800 nm is thickness of layer, C is concentration of atoms per cm3 but I am not sure concentration of what?)

2. C:GaN 700nm (C:2E19 at/cm3) (what is C before GaN and again concentration 2E19 at/cm3 of what?)

3. AlN/Al0.1GaN 5/25 nm (I do not know what 0.1 in Al0.1GaN means; I know that 5nm is Alluminiu Nitride, 25nm Alluminium Gallium Nitride)

4. Al0.3Ga0.7N (what means 0.3 and 0.7? I think it means that 30% of Al and 70% of Ga, but what about N (nitrogen)? is it 50% of Nitrogen and from remaining 50% is 30%Al and 70% of Ga so over all 50%N, 15%Al, 35%Ga? Am I wrong?

Thanks for answers!
 
Last edited by a moderator:
Chemistry news on Phys.org
epsilonpi said:
u-GaN 800nm (C:2E16 at/cm3) (I do not understand what "u" stands for; GaN is Gallium Nitride, 800 nm is thickness of layer, C is concentration of atoms per cm3 but I am not sure concentration of what?)
"u" means undoped. The C:2E16 is the concentration of carbon atoms in the gallium nitride.
epsilonpi said:
2. C:GaN 700nm (C:2E19 at/cm3) (what is C before GaN and again concentration 2E19 at/cm3 of what?)
Again, C is carbon here.
epsilonpi said:
AlN/Al0.1GaN 5/25 nm (I do not know what 0.1 in Al0.1GaN means; I know that 5nm is Alluminiu Nitride, 25nm Alluminium Gallium Nitride)
This means that aluminum is a dopant in GaN at up to 10 at%.
epsilonpi said:
Al0.3Ga0.7N (what means 0.3 and 0.7? I think it means that 30% of Al and 70% of Ga, but what about N (nitrogen)? is it 50% of Nitrogen and from remaining 50% is 30%Al and 70% of Ga so over all 50%N, 15%Al, 35%Ga? Am I wrong?
Thanks for answers!
This is just basic stoichiometry, but presented in a way that may not be familiar from intro chemistry classes (the convention is, however, standard in solid state chemistry and physics). Pure GaN has one gallium atom for every nitrogen atom. Al0.3Ga0.7N has 0.3 aluminum atoms and 0.7 gallium atoms for every nitrogen, so in terms of atom percent, it's 50% N,15% Al, 35% Ga.
 
  • Like
Likes   Reactions: epsilonpi
Thank you for your answer.
I am little bit confused why do we have concentration of Carbon in undoped u-GaN? There should be no Carbon or does it mean that even if it is clean GaN there is still some carbon present but we did not add it into GaN by purpose?
 
Last edited by a moderator:
Actually, I think I was wrong. I assume that the C:2E16 at/cm3 refers to the carrier concentration: so undoped GaN has no carbon in it, but the carrier concentration in this case would be 2E16 cm-3. What's throwing me off is the units of at/cm3, which implies an atomic dopant concentration, instead of a carrier concentration. Where are these numbers coming from?
 
Those numbers are parameters of layers in semiconductor parts. This is how they were fabricated. Thanks for your help.
 
epsilonpi said:
Those numbers are parameters of layers in semiconductor parts. This is how they were fabricated. Thanks for your help.
NB--The range of numbers (1016-1019) suggests an atomic dopant as well. Carrier concentrations tend to be 1012-1015 cm-3. You might check the supplier's data sheet on the semiconductor if you have it.
 
  • Like
Likes   Reactions: epsilonpi